Order Line Type - Inventory Interface "C" for G/L Account and Stock

We have tried to setup a new process using a custom line type (ZZ) with inventory interface set to "C". We are having problems with inventory PO receipt and receipt routing. We can receive the PO with no problems (P4312)...everything works great. However, when we try to process via Receipt routing (P43250) and try to specify the lot number and memo fields (using application P42053 where OP = '4' on routing screen) we end up having problems writing to the F43121 table and end up getting a blank GL Class Code written in PO receipts Ledger (F43121).

Has anyone seen this issue before. Oracle has raised a BUG for this problem but just thought I would post here is case someone has seen this before and has a workaround. I do have a workaround where we specify the lot number at PO receipt into DOCK but this will not work as receiver's may not know the location/memo at this point prior to inspection, etc.

Thanks!

FYI - I raised an issue with Oracle support and they now have a BUG for this. Hoping for a quick resolution but not optimistic as it may be a somewhat difficult fix involving many moving parts.